Edge Modbus TCP 点调用栈（含 RTU-over-TCP）

本文以配置点 phy_modbus_tcp_s1_r40001 为例，说明从 physical_devices.json 到硬件读数、再到 uplink 上报的完整调用路径。

运行时物理点 ID 为 {edgeId}/{physicalPointId}，例如 edge01/phy_modbus_tcp_s1_r40001。

1. 设计要点：没有独立的 TcpRtuIngress

edge 不按传输方式 创建 ingress，而按 protocol 创建：

配置字段	作用
`protocol: "modbus"`	走 `ModbusIngress`（串口 + TCP + RTU-over-TCP 共用）
`transport: "rtu"`	driver 层：`libmodbus` 串口
`transport: "tcp"`	driver 层：`libmodbus` 标准 Modbus TCP（MBAP）
`transport: "tcp_rtu"`	driver 层：`TcpRtuSession`（RTU 帧跑在 TCP 上）

自定义协议分支在 ModbusChannelManager 内，由 transport 字段触发，上层 ModbusIngress 无感知。

physical_devices.json (点)
        ↓
ModbusIngress（统一采集）
        ↓
ModbusChannelManager::openChannel / readRegisters
        ├─ transport: rtu     → libmodbus 串口
        ├─ transport: tcp     → libmodbus 标准 TCP
        └─ transport: tcp_rtu → TcpRtuSession

2. 配置锚点

{
  "physicalDeviceId": "phy_modbus_tcp_slave_255",
  "channelId": "eth_modbus_tcp_0",
  "protocol": "modbus",
  "slaveId": 255,
  "points": [
    {
      "physicalPointId": "phy_modbus_tcp_s1_r40001",
      "register": 40001,
      "function": 3,
      "scale": 0.1,
      "pollIntervalMs": 500
    }
  ]
}

{
  "channelId": "eth_modbus_tcp_0",
  "protocol": "modbus",
  "transport": "tcp_rtu",
  "host": "192.168.31.253",
  "tcpPort": 502
}

3. 阶段 A：启动（一次性）

flowchart TD
    A["main:52 runtime.init()"] --> B["EdgeRuntime::init:35 loadDevices"]
    B --> C["PhysicalRegistry::loadDevices:89 qualifyPointId"]
    C --> D["rebuildPollIndex:143 写入 pointIndex_"]
    D --> E["EdgeRuntime::rebuildIngress:16 createIngress"]
    E --> F["DeviceFactory::createIngress:34 ModbusIngress"]
    F --> G["ModbusIngress::open:24 openChannel(eth_modbus_tcp_0)"]
    G --> H{"transport == tcp_rtu?"}
    H -->|是| I["ModbusChannel::openChannel:39-51 TcpRtuSession::connect:31"]
    G --> K["PollPlanner::reset:18 注册点周期 500ms"]

步骤	函数	文件:行号	说明
1	`main`	`src/softbus_edge/src/main.cpp:52`	`runtime.init(config, ...)`
2	`EdgeRuntime::init`	`src/softbus_edge/src/EdgeRuntime.cpp:35`	`physicalRegistry_.loadDevices(..., edgeId)`
3	`PhysicalRegistry::loadDevices`	`src/softbus_edge/src/PhysicalRegistry.cpp:89-91`	JSON 解析，`qualifyPointId` → `edge01/phy_modbus_tcp_s1_r40001`
4	`PhysicalRegistry::rebuildPollIndex`	`PhysicalRegistry.cpp:142-145`	组装 `ResolvedPhysicalPoint{point, device, channel}` 写入 `pointIndex_`
5	`EdgeRuntime::rebuildIngress`	`EdgeRuntime.cpp:16-19`	`createIngress` → `ingress_->open()`
6	`DeviceFactory::createIngress`	`src/softbus_edge/src/DeviceFactory.cpp:33-35`	创建 `ModbusIngress`
7	`ModbusIngress::open`	`src/softbus_edge/src/ingress/modbus/ModbusIngress.cpp:23-24`	对所有 `protocol==modbus` 通道调用 `openChannel`
8	`ModbusChannelManager::openChannel`	`src/softbus_edge/src/driver/modbus/ModbusChannel.cpp:39-51`	`tcp_rtu` → `TcpRtuSession::connect(host, port)`
9	`TcpRtuSession::connect`	`src/softbus_edge/src/driver/modbus/TcpRtuSession.cpp:31-62`	TCP `socket` + `connect`，保存 `socketFd_`
10	`PollPlanner::reset`	`src/softbus_edge/src/scheduler/PollPlanner.cpp:9-18`	注册该点 `intervalMs=500`

启动成功后日志示例：

Opened RTU-over-TCP channel eth_modbus_tcp_0 192.168.31.253:502

4. 阶段 B：运行循环（每 50ms tick，点每 500ms 到期）

主循环：main.cpp:76 → EdgeRuntime::tick() → pollIngress() → ModbusIngress::poll()。

sequenceDiagram
    participant M as main.cpp:76
    participant RT as EdgeRuntime::tick:153
    participant PI as EdgeRuntime::pollIngress:141
    participant MI as ModbusIngress::poll:57
    participant PP as PollPlanner
    participant MPS as ModbusPollScheduler
    participant MCM as ModbusChannelManager
    participant TR as TcpRtuSession
    participant UL as UplinkClient

    M->>RT: tick()
    RT->>PI: pollIngress()
    PI->>MI: ingress_->poll()
    MI->>PP: duePointIds()
    MI->>MI: resolvePoint
    MI->>MPS: planBatches()
    MI->>MCM: readRegisters(startAddr, count)
    MCM->>TR: readHoldingRegisters(255, 0, 2)
    TR->>TR: transaction RTU send/recv
    TR-->>MCM: values
    MCM-->>MI: values
    MI->>MI: buildModbusFrame RawPacket
    PI->>UL: sendRawPacket (uplink 已连接时)

4.1 文本调用栈（带行号）

main.cpp:76
  └─ EdgeRuntime::tick()                          EdgeRuntime.cpp:153-156
       └─ EdgeRuntime::pollIngress()              EdgeRuntime.cpp:141-150
            └─ ModbusIngress::poll()               ModbusIngress.cpp:57-130
                 │
                 ├─ PollPlanner::duePointIds()    PollPlanner.cpp:22-31
                 │    → 含 "edge01/phy_modbus_tcp_s1_r40001"（500ms 周期）
                 │
                 ├─ PhysicalRegistry::resolvePoint()  PhysicalRegistry.cpp:183-190
                 │    → ResolvedPhysicalPoint {
                 │         point.registerAddress = 40001
                 │         device.slaveId = 255
                 │         channel.channelId = "eth_modbus_tcp_0"
                 │         channel.transport = "tcp_rtu"
                 │       }
                 │
                 ├─ ModbusPollScheduler::planBatches()  ModbusPollScheduler.cpp:31-104
                 │    → modbusAddress(40001) = 0
                 │    → 常与 r40002 合并 batch{startAddr=0, count=2}
                 │
                 ├─ ModbusChannelManager::readRegisters()  ModbusChannel.cpp:121-132
                 │    → channels_["eth_modbus_tcp_0"].tcpRtu 非空
                 │    └─ TcpRtuSession::readHoldingRegisters(255, 0, 2)  TcpRtuSession.cpp:97-137
                 │         ├─ 组 PDU: FF 03 00 00 00 02              :106-113
                 │         └─ TcpRtuSession::transaction(pdu)         :73-94
                 │              ├─ crc16 + append CRC               :79-82
                 │              ├─ send(socketFd_)                    :84
                 │              └─ recv(socketFd_)                    :88-94
                 │
                 ├─ ChangeFilter::shouldReport()   ModbusIngress.cpp:112-115
                 ├─ buildModbusFrame(255, raw)     ModbusIngress.cpp:44-54, :124
                 ├─ packet.sourceId = "edge01/phy_modbus_tcp_s1_r40001"  :122
                 ├─ packet.protocolTag = "modbus"                       :123
                 └─ PollPlanner::markPolled()        ModbusIngress.cpp:126
                      PollPlanner.cpp:34-41

            └─ UplinkClient::sendRawPacket(packet)  EdgeRuntime.cpp:147-148
                 └─ UplinkClient::sendRawPacket()    UplinkClient.cpp:30-32
                      └─ TcpUplinkClient::sendRawPacket()  (softbus_transport)

5. 自定义协议触发点（仅两处）

打开通道（一次性）：

    if (isTcpRtuTransport(channel)) {
        handle.tcpRtu = std::make_unique<TcpRtuSession>();
        if (!handle.tcpRtu->connect(channel.host, channel.tcpPort)) {
            // ...
        }

读寄存器（每次轮询）：

    if (it->second.tcpRtu) {
        return it->second.tcpRtu->readHoldingRegisters(
            point.device.slaveId, startAddr, count);

ModbusIngress 在 ModbusIngress.cpp:89 统一调用 readRegisters，不区分底层实现。

6. 本点一次读写的实际参数

项	值
`physicalPointId`	`edge01/phy_modbus_tcp_s1_r40001`
`channelId`	`eth_modbus_tcp_0`
`slaveId`	`255` → RTU 帧首字节 `0xFF`
`register 40001`	内部地址 `startAddr = 0`
合并读	常与 `r40002` 一次 `count=2`
网线 payload	`FF 03 00 00 00 02` + CRC（非 Modbus TCP MBAP）
上行 RawPacket	`protocolTag="modbus"`，payload 为模拟 0x03 响应帧

7. 为何需要 tcp_rtu

部分设备（如 192.168.31.253:502）在 TCP 502 端口上收发的是 Modbus RTU 帧，而非标准 Modbus TCP（无 MBAP 事务头）。

方式	结果
`transport: "tcp"` + libmodbus	连接成功，但读寄存器 `Invalid data`
`transport: "tcp_rtu"` + TcpRtuSession	读 slave 255 寄存器成功

daemon 侧仍用 protocol_modbus 解析上行 RawPacket，无需知道 底层是串口还是 RTU-over-TCP。

8. 与串口点的对比

层级	串口 `phy_modbus_s1_r40001`	TCP `phy_modbus_tcp_s1_r40001`
Ingress	同一 `ModbusIngress::poll`	同一 `ModbusIngress::poll`
openChannel	`ModbusChannel.cpp:55-76` libmodbus RTU	`ModbusChannel.cpp:39-51` TcpRtuSession
readRegisters	`modbus_read_registers`	`TcpRtuSession::readHoldingRegisters`
上行 protocolTag	`modbus`	`modbus`

9. 相关文档

softbus_edge.md — edge 总览
edge_device_setup.md — 配置与启动
UPLINK_WIRE_PROTOCOL.md — uplink 线协议

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